At the beginning of the round, 4 cards with different numbers are revealed in a 2x2 pattern.
Each player has five two-faced cards with 4 numbers on each of them, and must use 4 of them to create, as quickly as possible, a 3x3 grid where each number is present once (just like in Sudoku) and the 2x2 pattern of numbers is present as well.
The quickest player wins the round - the winner of the game is the first player to win 3 rounds.